Force NSDocument save panel to select most specific type in format popup button

Can you provide more information about the APIs you are using and how you are using them. Specifically, I think what you're doing with the allowedContentTypes and currentContentType NSSavePanel properties are the first things I'd like to look at.

I tried playing with those properties, but what I described above already happens without using any of them, and even when using them I wasn‘t able to find a combination that worked.

Can you provide a code listing showing how you are using these APIs? I'd like to try to reproduce what you are seeing there.

For instance take the following code:

class AppDelegate: NSObject, NSApplicationDelegate {
 
    func applicationDidFinishLaunching(_ aNotification: Notification) {
        DispatchQueue.main.async {
            let document = try! NSDocumentController.shared.makeUntitledDocument(ofType: "net.daringfireball.markdown")
            print(document.fileType!, UTType(document.fileType!)!)
            NSDocumentController.shared.addDocument(document)
            document.makeWindowControllers()
            document.windowControllers[0].window!.title = "Markdown"
            document.showWindows()
        }
    }
 
}

And Info.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>UTImportedTypeDeclarations</key>
	<array>
		<dict>
			<key>UTTypeConformsTo</key>
			<array>
				<string>public.plain-text</string>
			</array>
			<key>UTTypeDescription</key>
			<string>Markdown</string>
			<key>UTTypeIcons</key>
			<dict/>
			<key>UTTypeIdentifier</key>
			<string>net.daringfireball.markdown</string>
			<key>UTTypeTagSpecification</key>
			<dict>
				<key>public.filename-extension</key>
				<array>
					<string>md</string>
					<string>mdown</string>
					<string>markdown</string>
					<string>text</string>
				</array>
				<key>public.mime-type</key>
				<array>
					<string>text/markdown</string>
					<string>text/x-markdown</string>
					<string>text/x-web-markdown</string>
				</array>
			</dict>
		</dict>
	</array>
	<key>CFBundleDocumentTypes</key>
	<array>
		<dict>
			<key>CFBundleTypeName</key>
			<string>Plain Text</string>
			<key>CFBundleTypeRole</key>
			<string>Editor</string>
			<key>LSHandlerRank</key>
			<string>Default</string>
			<key>LSItemContentTypes</key>
			<array>
				<string>public.plain-text</string>
			</array>
			<key>NSDocumentClass</key>
			<string>$(PRODUCT_MODULE_NAME).Document</string>
			<key>NSUbiquitousDocumentUserActivityType</key>
			<string>org.desairem.uFocus.OpenDocument</string>
		</dict>
		<dict>
			<key>CFBundleTypeName</key>
			<string>Markdown</string>
			<key>CFBundleTypeRole</key>
			<string>Editor</string>
			<key>LSHandlerRank</key>
			<string>Default</string>
			<key>LSItemContentTypes</key>
			<array>
				<string>net.daringfireball.markdown</string>
			</array>
			<key>NSDocumentClass</key>
			<string>$(PRODUCT_MODULE_NAME).Document</string>
			<key>NSUbiquitousDocumentUserActivityType</key>
			<string>org.desairem.uFocus.OpenDocument</string>
		</dict>
	</array>
</dict>
</plist>

After making sure that the document with the window title Markdown is active, press Command-S to open the default save panel: Plain Text is selected instead of Markdown.